In my previous U.S. Pat. No. 4,455,870, issued on Jun. 26, 1984, a means is provided to measure flow through a pumping station utilizing constant speed pumps which cycle on and off. Typically, a pump will start pumping when the wet well reaches a "high" level, and will cease pumping when the wet well reaches a "low" level.
In my previous patent just mentioned, the determination of inflow during a pumping phase is accomplished by first determining the inflow rate over a single time segment closely preceding the pumping phase, and then extrapolating this calculated inflow over the duration of the pumping phase.
There are pumping stations where the system set forth in my above U.S. patent cannot be used, because the pumping stations utilize a plurality of pumps which are adapted to work either singly or in combinations. In such installations, a pumping phase may last too long to allow one to legitimately extrapolate a previously calculated inflow rate over the entire pumping phase.
Other approaches to the calculations of total flow through a pumping station are represented by the following prior art, of which the applicant is aware:
U.S. Pat. No. 2,859,616, issued Nov. 11, 1958, Fellows;
U.S. Pat. No. 3,376,744, issued Apr. 9, 1968, Kister et al;
U.S. Pat. No. 3,455,162, issued Jul. 15, 1969, Michener et al;
U.S. Pat. No. 3,177,711, issued Apr. 13, 1965, Ham et al;
U.S. Pat. No. 4,108,574, issued Aug. 22, 1978, Burtley;
U.S. Pat. No. 4,248,194, issued Feb. 3, 1981, Drutchas et al;
U.S. Pat. No. 4,467,657, issued Aug. 28, 1984, Olsson;
U.K. patent 2 077 434, published Dec. 16, 1981, Miller.